Next, follow the schematic diagram to complete the security alarm. The transmitter section uses a 12V (A23 type) battery as its power source. Fortunately, we can power the whole circuit from this ...

Normally, the fire alarm initiating device, notification appliance and signaling line circuits are not run outside the building. When we have no choice but to run them overhead or underground ...

But, still we are under tension, apprehending that somebody may cut the chain and steal our luggage. Here is a simple circuit to alarm you when somebody tries to cut the chain. T1 enables supply to ...